Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of
1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ¨

If an emerging growth company, indicate by check mark if the registrant has elected
not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant
to Section 13(a) of the Exchange Act. ¨

Item 5.07.

Submission of Matters to a Vote of Security Holders.

The 2017 annual meeting of stockholders
of Enzon Pharmaceuticals, Inc. (the “Company”) was held on June 28, 2017. At the 2017 annual meeting of stockholders,
the Company’s stockholders voted on the following matters as described in the Company’s proxy materials: (1) the election
of three directors, each for a one-year term expiring at the Company’s next annual meeting of stockholders and until such
director’s successor is elected and qualified, (2) the ratification of the appointment of EisnerAmper LLP as the Company’s
independent registered public accounting firm for the fiscal year ending December 31, 2017, (3) the approval, on an advisory basis,
of the compensation of the Company’s named executive officers and (4) to vote, on an advisory basis, on the frequency of
future advisory votes on the compensation of the Company’s named executive officers. A total of 36,535,647 shares of common
stock were present or represented by proxy at the 2017 annual meeting of stockholders, representing approximately 82.6% of the
total shares of common stock entitled to vote at the 2017 annual meeting of stockholders.

1.

Election of Directors – The Company’s stockholders elected each of the following individuals as a director
for a one-year term expiring at the Company’s next annual meeting of stockholders and until such director’s successor
is elected and qualified, as set forth below:

Nominee

Votes For

Votes Against

Abstentions

Broker Non-Votes

Jonathan Christodoro

17,227,424

636,517

84,119

18,587,587

Odysseas Kostas

17,242,865

653,102

52,093

18,587,587

Jennifer McNealey

17,275,132

579,005

93,923

18,587,587

2.

Ratification of the appointment of EisnerAmper LLP as the Company’s independent registered public accounting firm
for the fiscal year ending December 31, 2017 – This proposal was approved as set forth below:

Votes
For

Votes
Against

Abstentions

35,804,219

500,214

231,214

3.

Approval, on an advisory basis, of the compensation of the Company’s named executive officers – This proposal
was approved as set forth below:

Votes
For

Votes
Against

Abstentions

Broker
Non-Votes

17,121,216

711,146

115,698

18,587,587

4.

Vote, on an advisory basis, on the frequency of future advisory votes on the compensation of the Company’s named executive
officers – The Company’s stockholders voted for one year as the frequency of future advisory votes on the compensation
of the Company’s named executive officers, as set forth below:

One Year

Two Years

Three
Years

Abstentions

Broker
Non-Votes

15,719,609

165,542

1,987,886

75,023

18,587,587

Consistent with the recommendation of
the Board of Directors of the Company as set forth in the Company’s proxy statement for the 2017 annual meeting of stockholders
and the vote of the stockholders at the 2017 annual meeting of stockholders, the Company will include an advisory vote to approve
the compensation of the Company’s named executive officers in its proxy materials every year until the next required stockholder
vote on the frequency of future advisory votes on the compensation of the Company’s named executive officers.

Item 8.01.

Other Events.

Second Amendment and Settlement with Nektar

On June 26, 2017, the Company entered into
a Second Amendment to the Company’s Cross-License and Option Agreement (the “Agreement”) with Nektar Therapeutics
(“Nektar”) wherein Nektar agreed to buy-out all remaining payment obligations to the Company under the Agreement, and
in connection therewith, Nektar and the Company also agreed to settle a litigation pending before the Supreme Court of the State
of New York in which the Company alleged a breach of contract for Nektar’s failure to pay a post-patent expiration immunity
fee that the Company believes became payable under the Agreement (the “Litigation”). In consideration for fully paid-up
licenses under the Agreement and for the dismissal with prejudice of all claims and counterclaims asserted in the Litigation, Nektar
agreed to pay the Company the sum of $7.0 million, which satisfies all future obligations of royalty payments pursuant to the Agreement,
the first $3.5 million of which was paid within one business day of the effective date of the Second Amendment and the remaining
$3.5 million of which will be paid within one business day of January 5, 2018.

SIGNATURES

Pursuant to the requirements
of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned
hereunto duly authorized.